1. Field of the Invention
The present invention generally relates to optical modules used by communication devices for inputting and outputting electrical signals or optical signals. More specifically, the present invention relates to an optical module with a structure for locking the optical module.
2. Description of the Related Art
A communication device for inputting and outputting an electrical signal or an optical signal is designed in a module, and a module structure capable of inserting and removing an optical module into and from a module-receiving cage is known.
Examples of known communication devices designed in a module include an E/O module for converting an electrical data signal into an optical signal for transmission of the optical signal via an optical fiber, and an O/E module for converting an optical signal received via an optical fiber into an electrical data signal.
In the field of optical communication devices always aiming at a further size reduction, standardization of component specifications (MSA: Multi Source Agreement) is in progress and standards are specified regarding dimensions of the optical modules and cages, compatibility of optical/electrical interface units, and mechanical compatibility in inserting and removing the optical modules into and from the cages.
As a mechanism for inserting and removing the optical module into and from the cage, a structure, where a locking state of the optical module on the cage is turned off by rotating a bail of the optical module from a receiving position to a pulling-out position, is suggested in Japanese Patent Application Publication No. 2005-249892.
FIG. 1 is a perspective view of an inserting and removing mechanism of an optical communication device designed in a module seen from a lower side.
FIG. 1(A) shows a state where an optical module 1 is inserted in a cage 2. FIG. 1(B) shows where a locking state of the optical module 1 on the cage 2 is turned off by rotating a bail 3 of the optical module 1 from a receiving position to a pulling-out position in a direction indicated by an arrow 51. FIG. 1(C) shows the optical module 1 in the process of being removed from the cage 2 by the bail 3.
In FIG. 1(A), the bail 3 is rotated in the direction of arrow 50 to be oriented vertically in an embracing relationship with a connector-fitting unit 4. A lock pin 8 provided in a T-shaped tongue 7 of the optical module 1 is projected through a lock hole 6 formed in an I-shaped tongue 5 of the cage 2. Thus, the optical module 1 is held in the state locked to and restricted by the cage 2.
As shown in FIG. 1(B), when the bail 3 of the optical module 1 is rotated in the direction of arrow 51, plate cams 10 formed at the circumference of a rotational axle 9 are rotated in a direction of arrow 52 so that the T-shaped tongue 7 which is an elastic body is pushed down in a direction of arrow 53. Following the pushing-down of the T-shaped tongue 7, the I-shaped tongue 5 of the cage 2 is also flexed downward. As a result, the lock pin 8 projecting through the lock hole 6 is disengaged from the lock hole 6 so that the optical module 1 is released from being locked to the cage 2 to be freely movable.
As shown in FIG. 1(C), when the optical module 1 is pulled out in the direction of an arrow 54 while the bail 3 is rotated down, although the T-shaped tongue 7 is still pushed down, the I-shaped tongue 5 is separated from the T-shaped tongue 7 so as to be returned in a direction of an arrow 55 due to the elastic force of the I-shaped tongue 5.
FIG. 2 is a cut-away side view of a main part of the optical module 1 and shows cam operations of the bail 3.
As shown in FIG. 2(A), the optical module 1 is inserted in the cage 2 in a state where the bail 3 stands vertically, so that when a lock pin 8 projecting through a hole 11 moves, the I-shaped tongue 5 is urged in a lower direction and pushed down. Then, the lock pin 8 is engaged with the hole 11 of the housing 12 and the lock hole 6 of the cage 2 so that the I-shaped tongue 5 is stopped being urged. Thus, the optical module 1 is locked to the cage 2 so that insertion of the optical module 1 in the cage 2 is completed.
As shown in FIG. 2(B), in a case where the optical module 1 is removed from the cage 2, the bail 3 is operated in the direction of the arrow 51 so as to be rotated down and thereby the T-shaped tongue 7 is urged in the direction of the arrow 53 by the cam operations in the direction of the arrow 52 of the plate cam 10. As a result of this, the I-shaped tongue 5 of the cage 2 follows and is urged in the direction of the arrow 56 so that the lock pin 8 is removed from the hole 11 and the lock hole 6. By pulling the optical module 1 from the cage 2, when the lock pin 8 passes through the hole 11, the I-shaped tongue 5 is stopped being urged and returned to an original position.
In addition, Japanese Patent Application Publication No. 2005-189684 suggests an improved disconnect structure for SFP optical transceiver modules that uses a slide that travels relative to the module housing over a limited range. The slide has operating pieces which are elastically displaceable to elastically displace a spring plate of the cage in a direction to release the locked state. The slide initially moves relative to the module housing to deflect the spring plate downward and release the locked state. When the slide then reaches the end of its range of motion relative to the module housing, further withdrawal of the slide pulls the module housing along with it, removing the module from the cage.
Furthermore, Japanese Patent Application Publication No. 2004-125860 suggests a package having a lock mechanism which enables easy lock releasing and easy extraction and insertion of the package. The package having the lock mechanism includes a package main body provided with a nearly rectangular shaped body portion and a head portion positioned at the longitudinal front end of said body portion, a lever and a lever turning axle provided beneath the bottom of said head portion, said lever being provided so as to make a projection appear and disappear in a bottom plane of said body portion, with an acting end which has a projection and is extended to the body portion, and a forcing end existing at the front end of said head portion and being located at the opposite side of said acting end relative to said lever turning axle, a crank axle extending to the width direction of said package main body along the bottom of said head portion and fitting said forcing end of said lever to a crank portion, an arm which is integrated with said crank axle and is turnable along a side plane of said head portion, and a lever prolonged in the width direction of said package main body from said arm, when said lever is positioned over the head portion, said projection is exposed out of the bottom plane of said body portion, and when said lever is positioned in front of said head portion, said projection is accommodated in the bottom plane of said body portion.
In addition, United States Patent Application Publication No. 2003/0198025 and United States Patent Application Publication No. 2003/0198026 suggest a pluggable optical transceiver having a pivotable actuator assembly for quickly and easily removing the transceiver from a receptacle cage.
Furthermore, United States Patent Application Publication No. 2003/0142917 suggests a delatching mechanism including wedges that reside in pockets adjacent to a post on a module when the module is latched in a cage.
In addition, U.S. Pat. No. 6,439,918 suggests an integrated latching mechanism for use with a user pluggable electronic module, such as an optoelectronic transceiver module.
Furthermore, U.S. Pat. No. 6,430,053 suggests a pluggable transceiver module having a housing, an elongated member slidably mounted on the first side of the housing, a wedge on the internal end of the elongated member, and a rotatable lever.
In addition, International Application Publication No. 2005/093482 suggests an optical module that may be used in small-form factor pluggable applications and includes a delatching/latching mechanism.
Furthermore, International Application Publication No. 03/090322 suggests an advanced shielded modular plug connector assembly incorporating a removable insert assembly disposed in the connector housing, the insert assembly being adapted to optionally receive one or more electronic components.
Here, problems of the examples shown in FIG. 1 and FIG. 2 are discussed with reference to FIG. 3. In the examples shown in FIG. 1 and FIG. 2, engagement of the lock pin 8 and the lock hole 6 is achieved by holding the I-shaped tongue 5 due to the elastic force. Release of the engagement of the lock pin 8 and the lock hole 6 is achieved by rotating the bail 3 in the direction of the arrow 52 so that the elastic T-shaped tongue 7 is pushed down in the direction of the arrow 53 and the elastic I-shaped tongue 5 is bent downward.
Accordingly, due to degradation with time of the elastic T-shaped tongue 7 of the optical module 1, the engagement of the lock pin 8 and the lock hole 6 may become unstable. Furthermore, a fulcrum of downward bending of the T-shaped tongue 7 may not become stable so that the release of the engagement of the lock pin 8 and the lock hole 6 may not be performed stably.
In addition, as discussed above, when the bail 3 of the optical module 1 is rotated in the direction of the arrow 51 (see FIG. 2(b) and FIG. 3) in order to remove the optical module 1 from the cage 2 so that the bail 3 is rotated downward, the plate cam 10 is rotated in the direction of the arrow 52. Because of this, the elastic T-shaped tongue 7 is pushed in the direction of the arrow 53. As a result of this, a space S (see FIG. 3) is formed between the T-shaped tongue 7 and the lower surface of the optical module 1. If a stick shaped member such as a driver is inserted in this space S as shown in an unnumbered black arrow in FIG. 3, it may be possible to operate the T-shaped tongue 7.
In order to prevent access from outside to the T-shaped tongue 7, a wall part having a height (thickness) corresponding to the space S may be provided at a lower part of the optical module 1. However, since there is a limitation of the height of the optical module 1 in the standard MSA, it is not possible to provide a wall part which causes the optical module 1 to have a height (thickness) greater than that defined by the standard MSA.